Prong lock actuator



Nov. 16, 1965 s. c. RosKlN 3,217,510

PRONG LOCK AGTUATOR Filed July 29, 1963 4 Sheets-Sheet 1 Iii By SAMUEL C Ros/fw ATTORNEY Nov. 16, 1965 s. c. RosKlN 3,217,610

PRONG- LOCK ACTUATOR Filed July 29, 1963 4 sheets-Sheet 2 /N VEN TOR By SAMUEL C Ros/wv TWS'f/g ATTORNEY Nov. 16, 1965 s. c. RosKlN 3,217,610

PRONG LOOK ACTUATOR Filed July 29, 1965 4 Sheets-Sheet 5 /NvENToR B1 SAMUEL C. Ros/nw 7W Serf/fra ATTORNEY Nov. 16, 1965 s. c. ROSKIN 3,217,610

PRONG LOCK ACTUATOR Filed July 29, 1963 4 Sheets-Sheet 4 /NVE/vToR Bv SAMUEL C. RosK/N ATTORNEY United States Patent O 3,217,610 PRONG LOCK ACTUATOR Samuel C. Ruskin, 1502 Madrona Drive, Seattle, Wash. Filed July 29, 1963, Ser. No. 298,084 7 Claims. (Cl. 92-25) This invention provides a mechanical locking device for an actuator, more specically this invention provides a locking device for a hydraulic actuator piston when the hydraulic actuator is retracted. The purpose of the locking device is to keep the hydraulic actuator in a retracted position regardless of the uctuation or even failure of the retracting hydraulic uid pressure.

Many mechanical devices and applications require a telescopic strut locking mechanism. This locking mechanism must be such that the retracted position of two telescopic struts can be maintained even when the primary source causing strut retraction is removed. Such a primary source of retraction can be pressurized hydraulic fluid. The potential uses of my invention appear to be numerous. In the aircraft industry the lock actuator can be used for the actuation of and the locking of landing gear housing, well doors and in lght for hydraulically actuated surfaces such as ilaps and slats. This prong lock actuator may be used on ships and hydrofoils; and heavy duty equipment such as scrappers, bulldozers, locomotives and railroad switching equipment.

An object of this invention is to provide a locking device having a number of components; to provide such a locking device in which the locking mechanism cannot jam even when the hydraulic fluid is contaminated; to provide a locking device which is reliable; the provision of a locking device have low stress levels throughout the locking mechanism; a device having a low cost of fabrication; to provide a device having a manual unlocking provision in case the primary source of power fails; the provision for mounting a locked-unlocked indicator signal switch; the provision of such a device wherein the interior of the actuator barrel is not scraped during piston motion; a further object is the sequencing of the extending fluid pressure thus assuring an unlocked actuator piston prior to hydraulic loading of the piston so as to provide low-lock bearing stress levels during actuator unlocking and subsequent extention of the actuator; and the provision of a locking device having a low ratio of the locking device length to cylinder bore diameter. These and other important objects and advantages of the invention will be more particularly brought out upon reference to the accompanying drawings, the detail of the specification to the invention and the claims.

In the drawings:

FIGURE l is a longitudinal cross-sectional view through one species of the invention and illustrates the piston in a locked retracted position;

FIGURE 2 is a longitudinal cross-sectional view through the actuator shown in FIGURE l and illustrates the unlocked piston in a partially extended position;

FIGURE 3 is a longitudinal cross-sectional view through an other species of the invention and illustrates the piston in a locked retracted position;

FIGURE 4 is a longitudinal cross-sectional view through the actuator species shown in FIGURE 3 and illustrates the unlocked piston partially extended;

FIGURE 5 is a longitudinal cross-sectional view through another species of the invention having two locking prongs and illustrates the actuators pistonin a retracted locked state;

FIGURE 6 is a longitudinal cross-sectional View through another species of the invention having two locking prongs and illustrates the actuators piston in a retracted locked state; and,

ice

FIGURE 7 is an isometric View of the prong employed in the locking mechanism.

Referring to the drawings it is seen that in FIGURE l there is a hydraulic actuated locking device 10 having what may be considered four (4) legs 12, 14, 16 and 18 at substantially right angles to each other when viewed in the same plane. The legs 12 and 14 may be considered as actuator mounting trunnions. The leg 16 has a cylindrical passageway 20 in it and which extends to the main body of leg 18. At the outside end of the leg 16 there is a drilled passageway 22.

The leg 18 is larger in exterior diameter than leg 16 and has a cylindrical passageway 24 therein. Positioned in passageway 24 is an anchor plate 26. This anchor plate 26 has a circumscribing flange 28. On the exterior face of flange 28 facing leg 16, there is a circular recess 38 having an O-ring 32 therein and an additional circular recess 34, of a smaller diameter than the circular recess 30. The anchor plate 26 has a cylindrical shoulder 36 which on its outer end has an inwardly directed lip 38. The base of the anchor plate, the shoulder 36 and the lip 38 deiine a cavity. In the base of the anchor plate 26 there is a cylindrical passageway 40. Also in the base of the anchor plate 26 there is an orifice 5 connecting the circular recess 34 and the anchor plate cavity.

Also, positioned in the cylindrical passageway 24 is the actuators barrel 42 having a cylindrical bore 44 therein. In the inner part of the cylindrical passageway 24 there is a circular recess 46 and in this recess 46 there is an O-ring 48. This O-ring 48, as is readily appreciated, acts as a seal between the cylindrical passageway 24 and the barrel 42. In the barrel 42 there is a piston 50 having a piston head 52 and a circular recess 54 with an O-ring 56 in the recess 54. On the outer end of the piston 52, viz, that end in the passageway 44 in the: barrel 42 there is a piston head member 58, This head member 58 is slotted longitudinally and perpendicularly to the slots orientation so as to carry a pin 6i). On this pin 60 there is positioned a prong 62.

FIGURE 7 is an isometric View of the prong 62. It is seen that this prong has a body portion 64. At one end of the body portion 64 there is an enlarged head 66 and in the enlarged head 66 there is a machined shaft hole 68. The body portion 64 and the enlarged head 66 are substantially ilat on two sides. The enlarged head 66 has protruding flat regions 70 and 72 which serve as prong rotation stops limiting the prongs rotation about its axis (shaft hole 68) when mounted in the piston head slot by means of pin 60. At the outer end of the prong body 64 the prong 62 expands into a head 74. This segment of a curved head 74 cylinder has an outwardly directed shoulder 76. In the interior of the enlarged head 74 there is a drilled recess 78.

In the cylindrical passageway 2t) in the leg 16 is positioned a plunger 84. The plunger 84 has on one end an enlarged head 88. The head 8S is reduced down to a contact end 90. The contact end is machined to project through and slide in the cylindrical passageway 4t) in the anchor plate 26, and to tit into the drilled recess 78 of the prong 62. The body 86 of the plunger 84 is reduced to form an arm 92. In the passageway 20, and positioned around the body 86, is a compression spring 94. This is a coil spring and is positioned between the arm 16 at the end of the passageway 2d and the shoulder 89. Positioned on the arm 92 is a signal switch 96. A lever arm 98 connects the signal switch 96 to arm 92. Upon movement of the plunger 84 the lever arm 98 also moves. An O-ring recess 93 is machined on the enlarged plunger head 88 and an O-ring 95 is fitted into it.

In arm 12 there is a drilled passageway 100. In this passageway there is a fitting 102 which houses the tapped extend port of the actuator. The fitting 102 has a small passageway 104 which runs from the tapped outer end 106. The passageway 104 has radially directed passageways 108. Passageways S connect with a circular recess 110. In the body of the device 10 there is a passageway 112 connecting the circular recess 110 to the recess 34 in the anchor plate 26. O-ring recesses 97 and 99 and O-rings 101 and 103 prevent hydraulic fluid leakage between fitting 102 and arm 12.

The operation of this hydraulic actuator is as follows. Assume that the actuator is extended. In FIGURE 2 the piston is extended and assume that hydraulic pressure is applied to the piston so as to move it to the left. During the movement of the piston to the left a slight pressure buildup will occur in the actuator chamber to the left of the advancing piston. This increase in pressure causes the plunger 86 to move to the left against the spring and out of the cavity in the anchor plate. Prior to the piston bottoming on the anchor plate the prong will enter the cavity in the anchor plate. Upon cessation of the piston motion, after bottoming, the pressure to the left of the piston will drop to about fifty (50 lbs.) pounds per square inch (the assumed return pressure governed by a check valve) and the plunger will begin to travel to the right. The reduced end 90 of the plunger traveling to the right will contact the drilled recess '78 in the prong 62. This will force the prongs outer shoulder 76 downward into the anchor plate cavity so as to bear against the lip of the anchor plate 36 should an extending force be applied (thus providing a locking device). The hydraulic tluid replaced by the plunger during its travel to the right will escape through the orice(s) in the anchor plate and into the extend port 104. For unlocking, hydraulic pressure is applied in the drilled passageway 104. This hydraulic pressure forces oil into the passageway 112 and also into the circular recess 34. The pressure buildup in the circular recess 34 causes the plunger to move to the left. With the movement of the plunger to the left the prong is unlocked and the pressurized hydraulic fluid enters the anchor plate cavity through the now partially vacated cylindrical passageway 40 and loads the piston 50 and causes it to move to the right.

In case the hydraulic pressure is unavailable for actuator extension it is possible to unlock the piston by pulling on the stem or shaft 92 so as to pull the head 90 of the plunger 186 out of contact with the prong. This allows the piston 50 to move or be moved to the right.

FIGURES 3 and 4 show a modification of FIGURES 1 and 2. Single prong lock actuators 3 and 4 differ from the actuator described in FIGURES l and 2 through having the locking prong mounted to the hydraulic actuators head 1'24. The anchor plate cavity 15 is part of the piston 148 and the plunger 162 is located within the piston rod 146. This actuator comprises a body portion 122 having on one end an actuator head end 124 and at the other end the barrel housing 126. The lbarrel housing 126 has a cylindrical passageway 128 therein. At the inner end of the cylindrical passageway 128 there is a partially slotted iitting 130 having a circular base and a body portion 1312. In the body portion 132 there is a pin 134 which tits with prong 62. The prong 62 has previously been described and will not be described at the present time. In the passageway 128 there is a barrel 136 and in which barrel `136 is a cylindrical passageway 138. In the passageway 128 there is a circular recess 140 and in the recess 140 there is an O-ring 142. The function of the O-ring is to prevent leakage of hydraulic fluid around the barrel 136. In the cylindrical passagelway 138 there is positioned a piston 144 having a piston rod portion 146, an enlarged head 148 on one end. The end of the head 148 directed inwardly o-r positioned inwardly is recessed at 1'50 to form a cavity. Encircling th1s recess is a circular lip 152. The central portion of the piston rod i146 facing the circular lip 152 is bored passageway 1154. Near the cavity 150 there is a circular lrecess 156 and in which is positioned a snapring 158. Positioned in the passageway 154 is a plunger 160 having a main body portion 162, a head 164 and which head is reduced to a smaller diameter 166. The head 164 has a circumscribing recess 16H8 and in this recess 168 there is positioned an O-ring 171. The reduced end 166 projects through the snapring 1158 and into the cavity 150. At the junction of the body portion 162 and the head 164 there is a shoulder 170. A compression spring 172 is positioned in the bored passageway 154 and encircles the plunger body portion 162. One end of the spring 172 bears against the shoulder at the end of the drilled passageway I154 and the other end Abears against the shoulder 170. In the piston rod 144 there is a drilled passageway .174. It is seen that the dr-illed passageway 174 is on that end of the piston as opposed to bored passageway 154. A drilled passageway 176 connects the drilled passageways '174 and 154.

In the body portion 12,2 there is a drilled tapped passageway 180 serving as the extend port of the actuator. This passageway 1180 connects with the cylindrical passageway y128 behind the tting 130 or behind the single prong i62.

In operation, see FIGURE 4, with the piston extended the hydraulic pressure is applied to move the piston 144 to the left. In this instance the piston 144, the locking plate and the plunger 160 move to the left. The moving piston causes a sli-ght pressure buildup in the chamber to the left of the piston. This pressure buildup moves the plunger to the right against the compression spring. Before the piston bottoms prong 62 ts into the pistons locking plate cavity 1150. Upon the piston bottoming piston motion ceases and the pressure in the actuator chamber to the left of the piston is reduced and the spring 172 urges the plunger to travel to the left so that the plunger reduced head i166 contacts the prong 62 and forces the shoulder 76 to bear against the circular lip 152 of the anchor plate. In this manner the piston 144 is firmly locked 4in position.

In order to unlock the piston 144 yhydraulic fluid under pressure is applied through the tapped opening 180. This hydraulic fluid under pressure Ibears against the plunger 160 so as to move the same against the spring 172. With the plunger 160 moved inwardly with respect to the drilled passageway 154 the prong 62 is no longer in a locked position with respect to the lip 152 of the anchor plate. The hydraulic pressure forces the piston 144 to the right.

It is seen that in this species of the hydraulic actuator that there is a provision for a manually unlocking of the actuator, should the extend hydraulic pressure fail. This is achieved through extending the plunger shaft 145 through the entire length of the piston rod. A force pulling the plunger to the right against the spring causes manual unlocking.

In FIGURE 5 there is illustrated a hydraulic actuator 200 which is substantially the same as hydraulic actuator 10 in FIGURES 1 and 2. The difference between hydraulic actuator 200 and hydraulic actuator 10is that hydraulic actuator 200 has two prongs for locking the piston while hydraulic actuator 10 has one prong 62 for locking the piston.

In the hydraulic actuator 200 it is seen that there is an upper prong and a lower prong. The operation of the actuator 200 is the same as the actuator 10. Upon the movement of the piston 50 to the left the plunger 85 is moved to the left because of hydraulic pressure. With the piston 50 bottoming the two prongs are inside the cavity of the anchor plate. Then, with pressure to the left of this piston falling to fty (50 lbs.) pounds per square inch the plunger moves to the right spreading apart the two prongs. The shoulders of the prong contact the lip surrounding the cavity of the anchor plate and the piston 50 is anchored in position. To release the piston hydraulic pressure is applied through the tapped extended port so as toforce plunger 85 to the left unlocking the prong and the piston 50. moves to. the right. In case of failure of hydraulic pressure lor the hydraulic supply the piston 84 can be moved to the left by pulling the shaft or shank 92 to the left. The signal switch 96 is actuated with` the movement of the plunger 84 and the shaft 92 The signal switch can be used to indicate the movement of the plunger.

In FIGURE 6' there is illustrated a hydraulic actuator 220 which is` similar in construction to the hydraulic actuator 1,20 except that the single prong 62 is replaced by two prongs.V The method of operation of the hydraulic actuator 120 has been explained and will. not be repeated at this time with respect to 220. However, it is. to be noted that with` the piston 144 bottoming with respect to the actuator head endthe two prongs are spread apart by the plunger head 166. The shoulders of the two prongs bear against the lip 152 surrounding the cavity of the anchor plate. In this manner the piston 144 is locked in position, To unlock the piston pressure is applied to the extended port so as to. move the plunger 160 to the right so as to allow the two prongs to disengage themselves from the circular lip. 152 of the anchor plate and piston motion to the right begins.

The four species of the prong lock actuator previously described" are in effect telescopic struts whose locking and unlocking mechanism is activated by pressurized hydraulic fluid. However, these same prong lock actuators can be used as telescopic struts whose locking and unlocking mechanism is activated by external axial forces. The locking and unlocking operation of the telescopic struts activated by external axial forces resembles closely the previously described actuator operation. It differs in the following way: In order to retract the extended struts an external axial force is applied to the piston rod strut. As the piston nears its bottoming position, the spring loaded plunger comes into contact and bears upon the protruding prong. This bearing load causes the plunger to move back against the compression spring that vacates the anchor cavity. As the plunger retracts the prong advances into the cavity. Once the prong is inside the cavity it is free to flop outwards about its pivoted pin. The spring loaded plunger pushes the prong outwards and occupies the drilled recess 78 in the prong. The shoulders of the prong would bear against the lip of the cavity should an extending force be applied to the piston rod strut. In this manner the telescopic struts are firmly locked in the retracted position. In order to unlock the retracted locked struts the protruding plunger shaft is pulled against the spring thus freeing the prong and permitting the telescopic struts to be extended by use of an extending axial force. It is understood that when a telescopic strut operated by means of an external axial force configuration is used the O rings `and hydraulic ports shown on the accompanying drawing can be eliminated.

From the foregoing description of the invention it is seen that I have provided prong lock actuators which have relatively few parts, are of a straight forward positive locking action and have manual release means in case of a fluid power failure such as hydraulic or pneumatic power failure.

Having presented my invention what I claim is:

1. A prong lock actuator, said actuator comprising an actuator cylinder, an anchor plate, said anchor plate being juxtapositioned to said cylinder, said anchor plate having a base, integral circumscribing sides, and an inwardly directed lip on the sides, said base and sides an inwardly directed lip defining a cavity, an opening in the base, a plunger in said opening, said plunger capable of moving in said opening, a prong, said prong having a head and an outwardly directed shoulder on the head, said head being capable of passing between said lip and into the cavity of the anchor plate, and said plunger upon c-ontacting said head of the prong moving the head of the prong so that the outwardly directed shoulder is positioned so as not to be able to move past said lip and out of the cavity in the anchor plate, a piston in said cylinder, `and said prong being. pivoted` so as to be moved by said head.

2. A prong lock actuator, said prong lock actuator comprising an actuator cylinder, and anchor plate, said anchor plate being juxtapositioned to said cylinder, said anchor plate having a base, integral circumscribing sides, and an inwardly directed lip on said sides, said base and sides and. lip defining a cavity, a passageway in the base of said anchor plate, a plunger in said passageway and capable of moving therein, a prong, said prong having a head and an. outwardly directed` shoulder on said head, said head and outwardly directed shoulder being capable of passing said lip and into the cavity, with said head` in said cavity and said plunger bearing aga-inst said head said shoulder being in` such a position as to present a bearing face against the inner face of thel lip in the cavity and therefore be locked so as` not to` be able to pass the lip and out of the cavity, a` piston in said cylinder, and said prong being pivoted to said piston so as to be capable of rotating.

3. A` fluid actuated prong lock actuator, said actuator comprising an actuator cylinder, an anchor plate, said anchor plate being juxtapositioned to said cylinder, said anchor plate having a` base and integral circumscribing side and an inwardly directed annular lip, said base and side and lip defining a cavity, a passageway in said cavity, a plunger, said plunger being of such a size as to be able to move in said passageway, a piston in said cylinder, a prong, said prong being pivoted to said piston so as to be able to rotate thereon, said prong having a head, said head having an outwardly directed shoulder, `a recess in the head to receive said plunger, said head being capable of moving through the annular lip and into the cavity, with said head in the cavity and said plunger bearing against said heard said prong being positioned so that the outwardly directed shoulder presents a bearing surface against the inner face of the annular lip so as to be restricted in its movement out of the cavity, a passageway through said anchor plate, and said passageway being connected to :a source of fluid to allow a variance in the fluid pressure in the cavity to move the plunger out of Contact with the head of the prong.

4. A fluid actuated prong lock actuator, said actuator comprising an actuator cylinder, an anchor plate, said anchor plate being juxtapositioned to said cylinder; said anchor plate having a base and integral circumscribing side and an inwardly directed annular lip, said base and side and lip defining a cavity, a passageway in said cavity, a plunger, said plunger being of such as size as to be able to move in said passageway, a piston in said cylinder, two prongs, each of said prongs being pivoted to said piston so as to be able to rotate thereon, said prongs having a head, said head having an outwardly directed shoulder, a recess in the head to receive said plunger, said heads being capable of moving through the annular lip and into the cavity, with said heads in the lcavity and said plunger bearing against said heads said prongs being positioned so that the outwardly directed shoulder presents a bearing surface against the inner face of the annular lip so as to be restricted in its movement out of the cavity, a passageway through said anchor plate, and said passageway being connected to a source of uid to allow a variance in the fluid pressure in the cavity to move the plunger out of contact with the heads of the prongs.

5. A prong lock actuator, said actuator comprising an actuator cylinder, a piston, said piston having on its inner end an anchor plate, said anchor plate having a base and an integral circumscribing side and on the side an inwardly directed lip, a passageway in said base, a plunger in said passageway and capable of moving therein, a prong, said prong having a head, said head having an outwardly directed shoulder, said prong being pivoted so as to be able to move, said base and side and lip defining a cavity, said head and outwardly directed shoulder being capable of moving past the lip and into the cavity, and said plunger upon being in contact with the head so positioning the head that the outwardly directed shoulder presents a bearing surface against the inner face of the lip so as to be positioned in the cavity and not free for movement outside of the cavity.

l 6. A prong lock actuator, said prong lock actuator comprising an actuator cylinder, a movable piston, said piston having on its inner end an anchor plate, said anchor plate having a base and an integral circumscribing side and on the side an inwardly directed annular lip, said base and side and lip defining a cavity, a passageway in the base, a plunger in said passageway, said plunger capable of moving therein, a prong, said prong being pivoted t-o a structure, said prong having a head, said head having an outwardly directed shoulder, the head of said prong being capable of passing between the annular lip and into the cavity, said plunger upon being in` contact with the head of the prong so positioning the prong that the head presents a bearing surface on the outwardly directed shoulder which is in conflict with the inner face of the lip so as to prevent the prong moving out of the cavity so as to lock the piston in position, a passageway connecting with the cavity so as to allow a fluid in the cavity for movement of the plunger out of contact with the prong.

7. A prong lock actuator, said prong lock actuator comprising an4 actuator cylinder, a movable piston, said piston having on its inner end an anchor plate, said anchor plate having a base and an integral ciroumscribing side and on the side an inwardly directed annular lip, said base and side and lip dening a cavity, a passageway in the base, a plunger in said passageway, said plunger capable -of moving therein, two prongs, said prongs being pivoted to a structure, each of said prongs having a head, said head having an outwardly directed shoulder, the heads of said prongs being capable of passing between the annular lip and into the cavity, said plunger upon being in contact with the heads of the prongs so positioning the prongs that the heads presents a bearing surface on the outwardly ydirected shoulder which is in conflict with the inner face of the lip so as to prevent the prongs moving out of the cavtiy so as to lock the piston in position, a passageway connecting with the cavity so as to allow a uid in the cavity for movement of the plunger out of contact with the prongs.

References Cited by the Examiner UNITED STATES PATENTS 2,771,060 ll/l956 Allbright 92-24 3,003,471 10/1961 Bodem et al 92-24 RICHARD B. WILKINSON, Primary Examiner. 

1. A PRONG LOCK ACTUATOR, SAID ACTUATOR COMPRISING AN ACTUATOR CYLINDER, AN ANCHOR PLATE, SAID ANCHOR PLATE BEING JUXTAPOSITIONED TO SAID CYLINDER, SAID ANCHOR PLATE HAVING A BASE, INTEGRAL CIRCUMSCRIBING SIDES, AND AN INWARDLY DIRECTED LIP ON THE SIDES, SAID BASE AND SIDES AN INWARDLY DIRECTED LIP DEFINING A CAVITY, AN OPENING IN THE BASE, A PLUNGER IN SAID OPENING, SAID PLUNGER CAPABLE OF MOVING IN SAID OPENING, A PRONG, SAID PRONG HAVING A HEAD AND AN OUTWARDLY DIRECTED SHOULDER ON THE HEAD, SAID HEAD BEING CAPABLE OF PASSING BETWEEN SAID LIP AND INTO THE CAVITY OF THE ANCHOR PLATE, AND SAID PLUNGER UPON CONTACTING SAID HEAD OF THE PRONG MOVING THE HEAD OF THE PRONG SO THAT THE OUTWARDLY DIRECTED SHOULDER IS POSITIONED SO AS NOT TO BE ABLE TO MOVE PAST SAID LIP AND OUT OF THE CAVITY IN THE ANCHOR PLATE, A PISTON IN SAID CYLINDER, AND SAID PRONG BEING PIVOTED SO AS TO BE MOVED BY SAID HEAD. 